saac

Your flatmate was mean but that's a great story.  That's a neat looking spectroscope; could you use a CFF lamp for calibration?

Jim 

On 25/09/2021 at 07:24, Merlin66 said:

Very neat and tidy!

Jim,

The angle is approx 3.15 deg for a 100 l/mm grating.

The formula:

sin B = n*N*L

where B is the deviation angle, n, the number of lines (l/mm) N is the order of the spectra (usually one) and L the wavelength.

for a 100 l/mm grating, 1st order at 550nm (green)

sin B = 1*100*550*10^-6

B = 3.15 deg.

Ken

 

Thanks Ken, I recognise it now (n lambda = d sin theta) where d = grating gap .   So I take it we use green as a mid band for the wavelength  to set the angle - that all makes sense thanks.

Jim 

That is a nice clean setup you have made there .  How did you determine the angle for the grating ?

Jim 

Looking very fit for purpose. You will notice such a difference when you have your permeant setup.  

Jim  

That's very clever Gina and with your guide above it looks like a fairly doable mod. I would never have had the inclination nor the knowledge to consider that but I'm printing your guide off as I can see it coming in handy in the future.   Those little 28BYJ steppers are quire inexpensive and this just makes them more flexible. Thanks for that.  

Jim 

That's what I was thinking Gina, it's the lateral loads that I thought would be the problem in maintaining the precision in the location of the printer head - but he must have found a way to make it work to a satisfactory level at least.  I wonder, could an oversized heated bed be more easily made from something akin to a large radiator?  Easy enough to make a large surface area radiator, but maybe the temperature would not get high enough - just a thought.  In any respect he has a fascinating design for sure.

Jim

That is a fascinating design (hang printer), I'm surprised he is able to get rigidity in the system to keep precision in the printing.

Jim

When you say 

" Transfer of momentum and addition of velocities mask the velocity of the reference frame considered in motion, and the principle of relativity as a scientific concept prevents the detection of this motion"

What do you mean by "transfer of momentum", transfer between what?